Structure and registry of the silica bilayer film on Ru(0001) as viewed by LEED and DFT.

Silica bilayers are stable on various metal substrates, including Ru(0001) that is used for the present study. In a systematic attempt to elucidate the detailed structure of the silica bilayer film and its registry to the metal substrate, we performed a low energy electron diffraction (I/V-LEED) study. The experimental work is accompanied by detailed calculations on the stability, orientation and dynamic properties of the bilayer at room temperature. It was determined, that the film shows a certain structural diversity within the unit cell of the metal substrate, which depends on the oxygen content at the metal-bilayer interface. In connection with the experimental I/V-LEED study, it became apparent, that a high-quality structure determination is only possible if several structural motifs are taken into account by superimposing bilayer structures with varying registry to the oxygen covered substrate. This result is conceptually in line with the recently observed statistical registry in layered 2D-compound materials.

Mapping carbon and nitrogen isotopic composition of fingernails to demonstrate a rural-urban nutrition transition in the Center-West, Northeast, and Amazon regions of Brazil.

OBJECTIVE: The main objective of this study is to investigate diet patterns among rural and urban populations of the Center-West, Northeast, and Amazon regions of Brazil through the carbon and nitrogen isotopic composition of fingernails, recognizing that the extent of market integration is a key driver of food consumption. MATERIALS AND METHODS: In the Center-West, Northeast, and Amazon regions of Brazil, fingernails were sampled in clusters encompassing a major city, town, and rural village. A total of 2,133 fingernails were analyzed. Fingernails were clipped by donors using fingernail clippers. In the laboratory, samples were cleaned then weighed in small tin capsules before being isotopically analyzed for carbon and nitrogen. RESULTS: The overall mean δ13 C and δ15 N were -19.7 ± 2.8‰ and 10.6 ± 1.1‰, respectively. In the more remote villages, where access to food markets is more challenging, lower δ13 C prevails, suggesting that Brazilian staple foods (rice, beans, and farinha) still dominate. In areas with easier access to food markets, δ13 C values were higher, suggesting a change to a diet based on C4 plants, typical of a Brazilian supermarket diet. The variability among inhabitants in the same location expressed by a significant inverse correlation between δ13 C and δ15 N fingernail values suggested that "market integration" does not affect everyone equally in each community. DISCUSSION AND CONCLUSION: The nutrition transition has not yet reached some remote villages in these regions of Brazil or that the nutrition transition has not yet reached all residents of these remote villages. On the other hand, in several villages there is a considerable adherence to the supermarket diet or that some residents of these villages are already favoring processed food.

Carbon and Nitrogen Isotope Ratios of Food and Beverage in Brazil.

Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used not only in future forensic cases involving food authenticity, but also in human forensic anthropology studies. The δ13C and δ15N were determined in 1245 food items and 374 beverages; most of them made in Brazil. The average δ13C and δ15N of C3 plants were -26.7 ± 1.5‱, and 3.9 ± 3.9‱, respectively, while the average δ13C and δ15N of C4 plants were -11.5 ± 0.8‱ and 4.6 ± 2.6‱, respectively. The δ13C and δ15N of plant-based processed foods were -21.8 ± 4.8‱ and 3.9 ± 2.7‱, respectively. The average δ13C and δ15N of meat, including beef, poultry, pork and lamb were -16.6 ± 4.7‱, and 5.2 ± 2.6‱, respectively, while the δ13C and δ15N of animal-based processed foods were -17.9 ± 3.3‱ and 3.3 ± 3.5‱, respectively. The average δ13C of beverages, including beer and wine was -22.5 ± 3.1‱. We verified that C-C4 constitutes a large proportion of fresh meat, dairy products, as well as animal and plant-based processed foods. The reasons behind this high proportion will be addressed in this study.

Photodegradation influences litter decomposition rate in a humid tropical ecosystem, Brazil.

Solar radiation in general and UV radiation in particular have been recognized to stimulate plant litter decomposition through photochemical mineralization of organic molecules such as lignin and through facilitation of microbial decomposition in dryland ecosystems. However, little is known about how photodegradation may influence decomposition in other ecosystems not subject to moisture limitations and under what conditions photodegradation may be favored. Decomposition in humid tropical ecosystems is a complex process, and it can be influenced by a number of environmental factors that are distinct from arid and semi-arid ecosystems. To assess the mechanisms underlying photodegradation by ultraviolet B (UV-B) radiation in a humid tropical ecosystem, we designed a 300-day field experiment in a tropical site in Brazil with high levels of annual precipitation, compared to arid ecosystems, and exposed litter to three levels of radiation (full sun, UV-B removed, and shade) combined with a biocide treatment. Results show that after nearly one year of exposure, the microbial biomass was not affected by UV-B incidence, and this effect has not yet been fully understood for tropical ecosystems. Modeled using an exponential deceleration equation, the removal of UV-B radiation decelerated the plant litter decomposition rate for the control conditions by 21% compared to litter exposed to full sun. Interestingly, shaded litter exhibited similar mass loss compared to litter exposed to full sun. Furthermore, differences in the decay constant among radiation treatments due to the UV-B effect were independent of lignin loss. Overall, our study suggests that UV-B radiation contributed to plant litter decomposition through carbon losses but had no discernible effect on nitrogen, lignin, or cellulose loss specifically. Importantly, our results demonstrate that photodegradation occurs under humid tropical conditions, and further studies are necessary to examine the mechanisms of carbon loss.

Significant Dzyaloshinskii-Moriya interaction at graphene-ferromagnet interfaces due to the Rashba effect.

The possibility of utilizing the rich spin-dependent properties of graphene has attracted much attention in the pursuit of spintronics advances. The promise of high-speed and low-energy-consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. Here we demonstrate that chiral spin textures are induced at graphene/ferromagnetic metal interfaces. Graphene is a weak spin-orbit coupling material and is generally not expected to induce a sufficient Dzyaloshinskii-Moriya interaction to affect magnetic chirality. We demonstrate that indeed graphene does induce a type of Dzyaloshinskii-Moriya interaction due to the Rashba effect. First-principles calculations and experiments using spin-polarized electron microscopy show that this graphene-induced Dzyaloshinskii-Moriya interaction can have a similar magnitude to that at interfaces with heavy metals. This work paves a path towards two-dimensional-material-based spin-orbitronics.

Evolutionary heritage influences Amazon tree ecology.

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

Prognostic value of coronary and microvascular flow reserve in patients with nonischemic dilated cardiomyopathy.

BACKGROUND: Coronary and microvascular blood flow reserve have been established as important predictors of prognosis in patients with cardiovascular disease. The aim of this study was to assess the value of coronary flow velocity reserve (CFVR) and real-time myocardial perfusion echocardiography (RTMPE) for predicting events in patients with nonischemic dilated cardiomyopathy. METHODS: One hundred ninety-five patients (mean age 54 ± 12 years; 66% men) with dilated cardiomyopathy (left ventricular ejection fraction < 35% and no obstructive coronary disease on invasive angiography or multidetector computed tomography) who underwent dipyridamole stress (0.84 mg/kg over 10 min) RTMPE were prospectively studied. CFVR was calculated as the ratio of hyperemic to baseline peak diastolic velocities in the distal left anterior coronary artery. The replenishment velocity (ß), plateau of acoustic intensity (A(N)), and myocardial blood flow reserve were obtained from RTMPE. RESULTS: Mean CFVR was 2.07 ± 0.52, mean A(N) reserve was 1.05 ± 0.09, mean ß reserve was 2.05 ± 0.39, and mean myocardial blood flow reserve (A(N) × ß) was 2.15 ± 0.48. During a median follow-up period of 29 months, 45 patients had events (43 deaths and two urgent transplantations). Independent predictors of events were left atrial diameter (relative risk, 1.16; 95% confidence interval, 1.08-1.26; P < .001) and ß reserve ≤ 2.0 (relative risk, 3.22; 95% confidence interval, 1.18-8.79; P < .001). After adjustment for ß reserve, CFVR and myocardial blood flow reserve no longer had predictive value. Left atrial diameter added prognostic value over clinical factors and left ventricular ejection fraction (χ2 = 36.8-58.5, P < .001). Beta reserve added additional power to the model (χ2 = 70.2, P < .001). CONCLUSIONS: Increased left atrial diameter and depressed ß reserve were independent predictors of cardiac death and transplantation in patients with nonischemic dilated cardiomyopathy. Beta reserve by RTMPE provided incremental predictive value beyond that provided by current known prognostic clinical and echocardiographic factors.

[Cardiac sinus node dysfunction due to a new mutation of the SCN5A gene]. / Une dysfonction sinusale en rapport avec une nouvelle mutation faux-sens du gène SCN5A.

A 10-year-old child was hospitalized for bradycardia during a viral infection with chikungunya. His history showed unexplored episodes of bradycardia. Cardiologic explorations revealed cardiac sinus node dysfunction (SD). Mutational screening of the SCN5A gene showed that this case was a compound heterozygote for p.Ala735Val and p.Asp1792Asn missense mutants. Five years later, the child underwent a pacemaker insertion after an electrophysiological study performed during an atrial flutter access.

Advances on surface structural determination by LEED.

In the last 40 years, low energy electron diffraction (LEED) has proved to be the most reliable quantitative technique for surface structural determination. In this review, recent developments related to the theory that gives support to LEED structural determination are discussed under a critical analysis of the main theoretical approximation-the muffin-tin calculation. The search methodologies aimed at identifying the best matches between theoretical and experimental intensity versus voltage curves are also considered, with the most recent procedures being reviewed in detail.

Desempenho hemodinâmico e resposta inflamatória durante o uso do DAV-InCor como ponte para o transplante / Hemodynamic performance and inflammatory response during the use of VAD-InCor as a bridge to transplant

FUNDAMENTO: O transplante cardíaco enfrenta o grave problema da escassez de doadores. Estima-se que entre 20 por cento e 40 por cento dos pacientes falecem na fila de espera. Para esses pacientes, a utilização de dispositivos de assistência circulatória é, muitas vezes, a única possibilidade de sobrevivência durante a espera do doador. No Brasil, não existe nenhum programa regular de utilização desses dispositivos como ponte para transplante. OBJETIVO: Avaliar o desempenho hemodinâmico e a resposta inflamatória durante a utilização do DAV-InCor como ponte para transplante. MÉTODOS: Entre outubro de 2003 e abril de 2006, 11 pacientes, indicados em caráter de prioridade para o transplante cardíaco, evoluíram em choque cardiogênico refratário. O implante do DAV-InCor foi realizado em sete pacientes. O diagnóstico etiológico foi cardiopatia chagásica em cinco pacientes e cardiomiopatia dilatada idiopática em dois. RESULTADOS: A assistência mecânica ao ventrículo esquerdo foi mantida nos sete pacientes por períodos entre 14 e 42 dias (média 26,2). O desempenho hemodinâmico foi adequado, com a normalização do índice cardíaco, dos níveis de saturação venosa de O2 e do lactato. O transplante foi realizado em dois pacientes, os outros cinco faleceram por infecção sistêmica ou falência de múltiplos órgãos. CONCLUSÃO: O desempenho do DAV-Incor, no comportamento hemodinâmico dos pacientes estudados, foi adequado para a manutenção de uma condição circulatória satisfatória durante o período estudado. Houve melhora dos parâmetros de perfusão tecidual e manutenção de sinais de resposta inflamatória sistêmica. Houve alta incidência de complicações; contudo, não foram demonstradas complicações relacionadas ao dispositivo que comprometam a segurança da utilização do mesmo.

BACKGROUND: Cardiac transplantation faces the serious problem of lack of donors and it is estimated that 20 to 40 percent of the patients die while waiting for heart transplantation. For these patients, the use of mechanical circulatory assist devices is the only choice of survival while waiting for a donor. In Brazil, the experience with mechanical circulatory support is limited and there is no regular program regarding the use of these devices as a bridge to heart transplantation. OBJECTIVE: To evaluate the hemodynamic performance and the systemic inflammatory response during the clinical use of the InCor-type ventricular assist device (VAD-InCor) as a bridge to heart transplantation. METHODS: Between October 2003 and April 2006, 11 patients in the waiting list for heart transplantation presented hemodynamic deterioration due to refractory cardiogenic shock. Seven of these patients were submitted to VAD-InCor implantation for left ventricular assistance. The etiologic diagnosis was Chagas' disease in 5 patients and idiopathic dilated cardiomyopathy in 2. RESULTS: The duration of left ventricular assistance ranged from 14 to 42 days (mean 26.2 days). During this period, the hemodynamic performance of the DAV-InCor was adequate to support a normal hemodynamic state. There was normalization of central venous oxygen saturation and serum lactate. Two patients were submitted to heart transplantation, while the other 5 patients died under assistance due to infection and multiple organ failure. CONCLUSION: The performance of the VAD-InCor, in the hemodynamic behavior of the studied patients, was adequate for the maintenance of a satisfactory circulatory state during the studied period. There was improvement in the tissue perfusion parameters and maintenance of systemic inflammatory response signs. There was a high incidence of complications; however, complications related to the device, which could compromise the safety of its use, were not demonstrated.

Benefit with methylprednisolone in continuous pulsetherapy in progressive primary form of multiple sclerosis: study of 11 cases in 11 years.

Primary progressive multiple sclerosis (PPMS) is defined clinically with a progressive course from onset. There is no approved treatment for the PPMS. Methylprednisolone IV (MP) hastens the recovery from MS relapses. We studied 11 patients that met the MacDonald's diagnostic criteria for PPMS. The dose of MP was 30 mg/kg in 250 mL of glucose solution in three consecutive days during the first week, two doses during the second and one dose in the third week. One weekly session for eight consecutive weeks was given. After, a once-a week/eight-week interval was maintained. The medium EDSS before treatment was 6.2, and after 11.2 years of treatment, the EDSS was 4.9. Although we studied a small sample of PPMS we may conclude that therapy with IVMP prevents clinical worsening of MS in the majority of patients with improvement in EDSS scores.

Benefit with methylprednisolone in continuous pulsetherapy in progressive primary form of multiple sclerosis: study of 11 cases in 11 years / Benefício do uso de pulsoterapia contínua com metilprednisolona na forma primária progressiva da esclerose múltipla: estudo de 11 casos em 11 anos

Primary progressive multiple sclerosis (PPMS) is defined clinically with a progressive course from onset. There is no approved treatment for the PPMS. Methylprednisolone IV (MP) hastens the recovery from MS relapses. We studied 11 patients that met the MacDonald's diagnostic criteria for PPMS. The dose of MP was 30 mg/kg in 250 mL of glucose solution in three consecutive days during the first week, two doses during the second and one dose in the third week. One weekly session for eight consecutive weeks was given. After, a once-a week/eight-week interval was maintained. The medium EDSS before treatment was 6.2, and after 11.2 years of treatment, the EDSS was 4.9. Although we studied a small sample of PPMS we may conclude that therapy with IVMP prevents clinical worsening of MS in the majority of patients with improvement in EDSS scores.

A forma progressiva da esclerose múltipla (FPEM) é definida como progressiva desde o início. Não há tratamento eficaz para esta forma. A metilprednisolona por via endovenosa (MPEV) é usada para os surtos de exacerbação da EM. Estudamos 11 pacientes que preenchiam os critérios de MacDonald para FPMS. A dose inicial de MPEV foi de 30 mg/kg em 250 mL de soro glicosado por três dias consecutivos na primeira semana, duas doses na segunda e uma dose na terceira semana. Seguiu-se uma sessão semanal por oito semanas. Após manteve-se uma dose semanal a cada oito semanas. A média do EDDS foi 9,6 antes e 4,9 após 11,2 anos de tratamento. Embora tenhamos estudado número reduzido de casos, podemos dizer que o uso de MPEV impede a progressão da FPEM na maioria dos pacientes estudados com melhora do EDDS.

Videoconference pediatric and congenital cardiology consultations: a new application in telemedicine.

BACKGROUND: The relative rarity of congenital heart disease gives it an orphean disease status, requiring specialised centres. The present maturity of information technology allows telemedicine to be integrated into current medical practice. We report our experience of telemedicine between the cardiology department at St Pierre Hospital on the island of Réunion and the pediatric cardiology department at the teaching hospital in Toulouse. AIMS: The aims of this work were to 1. verify the technical feasibility of transmitting echocardiographic images, 2. determine an optimal therapeutic strategy for each patient, and 3. deliver precise information live to patients and their families. METHODS: Five pediatric cardiology videoconference consultation sessions were transmitted between April 2006 and May 2007. The videoconference equipment, POLYCOM VSX 7000 (R), was used to relay information between the two centres, using six high-debit digital telephone lines, allowing a transfer rate of 384 kbits/s and an image frequency of 25 frames per second. The echocardiographic equipment at St Pierre Hospital was connected to the videoconference equipment by an S-VHS video output. The transmitted sources alternated between the echographic video output and the signal from a video camera, with continuous audio transmission. RESULTS: The telemedicine meeting was made up of three main elements: 1. a consultation with real-time echocardiographic acquisition and transmission, 2. a discussion between medical colleagues, and 3. a discussion with the family. Five videoconference consultation sessions were organised between April 2006 and May 2007. 22 patients were involved (median age 3 years, age range 7 days to 48 years). Heart disease was congenital in 20 patients, and acquired in 2 patients. The aim of the telemedicine consultation was to specify: 1. medical treatment in 7 patients, and 2. an indication for surgery or interventional catheterisation in 15 patients. There was no significant change in diagnosis, but in 2 patients with complex heart disease some anatomical clarifications were made. For 3 patients, the videoconference discussion was essential to get the extremely reticent families to accept the indication for surgery. CONCLUSION: This is the first experience in France of telemedicine consultation for pediatric and congenital cardiology. These videoconferences allowed patients in the south of Réunion to benefit from a specialist opinion on optimal therapeutic strategy, with no delay or need to travel a long distance.

Hemodynamic performance and inflammatory response during the use of VAD-InCor as a bridge to transplant.

BACKGROUND: Cardiac transplantation faces the serious problem of lack of donors and it is estimated that 20 to 40% of the patients die while waiting for heart transplantation. For these patients, the use of mechanical circulatory assist devices is the only choice of survival while waiting for a donor. In Brazil, the experience with mechanical circulatory support is limited and there is no regular program regarding the use of these devices as a bridge to heart transplantation. OBJECTIVE: To evaluate the hemodynamic performance and the systemic inflammatory response during the clinical use of the InCor-type ventricular assist device (VAD-InCor) as a bridge to heart transplantation. METHODS: Between October 2003 and April 2006, 11 patients in the waiting list for heart transplantation presented hemodynamic deterioration due to refractory cardiogenic shock. Seven of these patients were submitted to VAD-InCor implantation for left ventricular assistance. The etiologic diagnosis was Chagas' disease in 5 patients and idiopathic dilated cardiomyopathy in 2. RESULTS: The duration of left ventricular assistance ranged from 14 to 42 days (mean 26.2 days). During this period, the hemodynamic performance of the DAV-InCor was adequate to support a normal hemodynamic state. There was normalization of central venous oxygen saturation and serum lactate. Two patients were submitted to heart transplantation, while the other 5 patients died under assistance due to infection and multiple organ failure. CONCLUSION: The performance of the VAD-InCor, in the hemodynamic behavior of the studied patients, was adequate for the maintenance of a satisfactory circulatory state during the studied period. There was improvement in the tissue perfusion parameters and maintenance of systemic inflammatory response signs. There was a high incidence of complications; however, complications related to the device, which could compromise the safety of its use, were not demonstrated.

[Lymphocytis meningitis: Listeria monocytogenes is a potential risk in a immunocompetent child]. / Méningite lymphocytaire: Listeria monocytogenes, une étiologie à ne pas négliger chez l'enfant immunocompétent.

UNLABELLED: Meningoencephalitis due to Listeria monocytogenes is a rare and serious form of brainstem infection in childhood. OBSERVATION: We report the case of a 7 year-old girl presenting lymphocytic meningitis with a high CRP level. Parenteral antibiotics combining ceftriaxone and vancomycine led initially to clinical improvement. Ten days later, secondary brainstem inflammation with hydrocephalus appeared and led to the detection of L. monocytogenes during external ventricular bypass. CONCLUSION: This observation of paediatric lymphocytic meningoencephalitis suggests a prescription of amoxicillin in association with first line antibiotics, particularly when an important inflammatory syndrome exists, immunocompetent children included.

The generalized simulated annealing algorithm in the low energy electron diffraction search problem.

We present in this work results concerning the application of the generalized simulated annealing (GSA) algorithm to the LEED search problem. The influence of the visiting distribution function (defined by the so-called q(V) parameter) in the effectiveness of the method was investigated by the application of the algorithm to structural searches for optimization of two to ten parameters in a theory-theory comparison for the CdTe(110) system. Results, obtained with the scaling relation and probability of convergence as a function of the number of parameters to be varied, indicate the fast simulated annealing (FSA) (q(V) = 2.0) approach as the best search machine.